1. Field of the Invention
The present invention relates generally to electronic devices and, in a preferred embodiment thereof, more particularly provides a computer with a specially designed heat sink structure incorporated therein.
2. Description of Related Art
It is well known in the electronic device design art that electronic components utilized in the manufacture of, for example, computers produce heat when they are operating in the computers. It is also well known that each electronic component has a maximum operating temperature and that if an electronic component is operated at a temperature greater than its maximum operating temperature, its useful life will be curtailed. Thus, the operating temperatures of electronic components within a computer must be controlled for the computer to function properly and for the computer to have an acceptable useful life.
A common method of controlling the operating temperatures of electronic components within a computer or other electronic device is to force a stream of ambient air across the electronic components. As the air passes over the electronic components, convective heat transfer occurs between the electronic components and the air, enabling the air to carry away heat generated by the electronic components during operation thereof. Typically, the stream of ambient air is produced by a relatively flat axial fan mounted to a housing enclosing the electronic components. The housing usually has openings therethrough for circulation of the air through the housing.
The forced air heat dissipation method has several disadvantages, however. A fan consumes power which might be utilized to operate other components of the computer. In modern battery powered notebook and subnotebook computers, minimized power consumption is desirable in order to achieve an acceptable battery operating time.
A fan capable of moving a sufficient volume of air to control the temperatures of electronic components in a modern computer usually takes up a large amount of space. Typically, an axial fan utilizes approximately two cubic inches within a computer housing. In a modern notebook or subnotebook computer, space is at a premium.
A fan has reliability concerns. As with any device having moving parts, the moving parts eventually wear out and require repair or replacement. A fan is also electrically operated, typically having an electric motor for rotating a fan blade. The electric motor, electrical contacts, etc. may also need repair or replacement. Another disadvantage is that the moving and electrical parts usually produce undesirable noise.
The forced air heat dissipation method is not very efficient since, typically, the air is delivered to all electronic components within the computer housing. The result is that the gross ambient air temperature within the housing may be reduced, but a particular electronic component which produces a large amount of heat may not receive the additional air flow necessary to maintain its temperature below its maximum operating temperature. In that situation, it is usually necessary to add a finned heat sink to the electronic component, which typically must be near the electronic component, takes up a large volume within the computer housing, and decreases the overall packaging efficiency of the computer.
A further disadvantage of a fan is that it cannot be contoured to fit in available space within a computer housing. For example, a modern subnotebook computer may have a sufficient volume of unoccupied space within its housing for an axial fan to fit therein, but that volume may be distributed throughout the housing. It simply is not possible to distribute portions of the fan to different areas of the housing and have the fan operate properly.
Another solution that has been proposed for dissipating heat generated in a computer is to attach one end of a heat pipe to a heat-producing component and the other end of the pipe to a portion of the computer's metal chassis. In this way, a particular component which generates a large amount of heat may be directly cooled. This method also has disadvantages, however. A disadvantage of the method is that it relies almost exclusively on conductive heat transfer through the computer chassis to dissipate the heat. The heat is eventually transferred to the environment via convection, but since the chassis is typically disposed within a housing, if the convective heat transfer is not assisted by a forced air method, it is very inefficient.
Heat pipes are at times provided with fins at one end thereof to permit convective heat transfer therefrom. Such fins are typically soldered or brazed to the heat pipes. A disadvantage of this method is that the soldering or brazing operations can cause damage to the heat pipes which may not be discovered until the heat pipes are installed in computers, the computers are operated, and components fail due to excessive heat. Another disadvantage of this method is that the fins must be mounted to the computers' chassis, but cannot form structural portions thereof. Furthermore, the fins are subject to damage during assembly which can affect the fit of the computer and lower the effectiveness of the thermal transfer.
From the foregoing, it can be seen that it would be quite desirable to provide an efficient means of dissipating heat generated by components within a computer housing which consumes no power, takes up minimal space in the housing, makes no noise, has no moving or electrical parts, may be contoured to f it within available space in the housing, may be adapted to dissipate heat generated by particular components, does not require soldering, brazing, or similar operations, and may be a structural portion of a computer chassis. It is accordingly an object of the present invention to provide such a heat dissipation means.